Project Impact: An Innovative Approach to Weight Loss Maintenance

1R01DK100345-01A1: An Innovative, Physical Activity-focused Approach to Weight Loss Maintenance

The major goal of this project is to evaluate an innovative approach to obesity. This study will determine if behavioral treatment can be improved by 1) implementing a primary focus on PA following initial weight loss treatment, and 2) using a novel, acceptance-based approach to the promotion of PA.

Most adults who engage in lifestyle modification find it difficult to maintain a high level of PA over the long-term, and most also find that weight regain is inevitable. The current portfolio of available interventions does not adequately address these challenges. This project is designed to test the effectiveness of an intervention that is specifically designed to enhance the ability to maintain, in the long-term, a level of PA high enough to achieve long-term weight loss maintenance.

In the study, 300 obese adults will be recruited from the community and provided with 6 months of group-based, standard behavioral treatment for induction of weight loss (Phase I). A 6-month Phase I was chosen so that all participants will have sufficient time to accomplish initial weight loss before Phase II begins, allowing Phase II to truly be a test of weight loss maintenance. In Phase II, participants will receive one of three interventions, to be delivered for an additional 12 months: 1) behavioral treatment, with the standard emphasis on maintaining changes in diet and PA (BT), 2) behavioral treatment, with a primary emphasis on using these skills to maintain PA (BT-PA), or 3) acceptance-based behavioral treatment, with a primary emphasis on using these skills to maintain PA (ABT-PA).

Assessments will be conducted at baseline, 6 months, 18 months (end of treatment), 24 months (6-month follow-up), and 36 months (18-month follow-up).

Inclusion Criteria:

• Have a BMI between 27 and 45 kg/m2
• Have the ability to engage in at least 15 minutes of moderate physical activity (e.g. brisk walking)
• Successfully complete all steps in the enrollment process, including attendance at all pre-randomization clinic visits and providing physician clearance

Exclusion Criteria:

• Have a medical condition that prevents safe engagement in moderate-to-vigorous physical activity
• Are lactating, pregnant, or planning to become pregnant in the next three years
• Report recently beginning a course of or changing the dosage of prescription medications that can cause significant weight loss or weight gain
• Are participating in or plan to participate in another weight loss program in the next three years
• Have a primary family member or member of their household participating in the study